The comedy "Bad Moms " fancies itself a "Hangover" for the PTA set. And, while a wild send-up of modern parental perfection — that insidious idea that exists only in commercials and glossy magazines — is a worthy and fresh subject for a fun summer comedy, "Bad Moms" is ultimately rather conventional.

Set in an upper middle class Chicago suburb, "Bad Moms" centers on Amy (Mila Kunis), a perpetually stressed and overworked 32-year-old with a part time job and two super busy pre-teens. Lest you think Kunis is a little too young to have pre-teens, the first line in the movie has her explaining that she got pregnant at 20. The movie is on the defense before it even gets going.

Amy spends her days shuttling her kids (Oona Laurence and Emjay Anthony) from school to soccer practice to Russian lessons. She puts up with grief from her incompetent 20-something boss (Clark Duke), her loser husband Mike (David Walton) and the mean moms of the PTA (Christina Applegate, Jada Pinkett Smith, Annie Mumolo). She does her son's school projects for him and apologizes profusely to her ungrateful family for being late with the beautiful homemade roast chicken she's made for dinner while her husband sits around like a dope. And she does all of this while still maintaining perfect hair, makeup and clothes.

Her breaking point comes when she realizes her spouse is not only a lazy dope, but also cheating on her with a woman from the internet. This is revealed in an unfunny bit that goes on far too long. But, after kicking him out, Amy decides to just start saying no to things — to four-hour PTA meetings, to insane dietary restrictions at the bake sale, and to working full time when her boss only pays her for three days a week.

She teams up with some similarly disgruntled mothers, including stay-at-home-mom Kiki (Kristen Bell) and single mom Carla (Kathryn Hahn). The actresses help elevate these characters above the stereotypes — especially Bell, who brings a lot of empathy and humor to what could have easily been a train wreck of a part.

The film does have its moments. It's kind of delightful when Amy plops down at the bake sale with a half-eaten container of doughnut holes. But for the most part, Amy's rebellion involves partying, shopping, daytime movies and cruise rides in her husband's fancy convertible. It feels a little bit like a frat bro's fantasy of "Mom's day off."

Perhaps that's because this film is from writer/directors Jon Lucas and Scott Moore — the screenwriters behind "The Hangover" and the party movie "21 & Over." It makes me wish they had called on Mumulo, who co-wrote "Bridesmaids," for an assist.

The saving grace is in the oddball friendship between Amy, Kiki and Carla. But everything goes off the rails in the third act. Amy's big moment centers around her trying to get elected head of the PTA over Applegate's character so that her daughter isn't unjustly benched on the soccer team. It contradicts her original point that they work too hard for their kids.

"Bad Moms" had so many opportunities to be great, edgy and insightful, but instead settles for the most milquetoast commentary possible on modern motherhood.

"Bad Moms," an STX Entertainment Release, is rated R by the Motion Picture Association of America for "sexual material, full frontal nudity, language throughout, and drug and alcohol content." Running time: 101 minutes. One and a half stars out of four.